61 research outputs found

    Sviluppo di sistemi di controllo di velivoli basati sull'inversione dinamica

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    E' stato sviluppato un esempio di sistema di controllo basato sul metodo dell’inversione dinamica a partire da un modello non lineare dell’aeroplano F-16. Esso è stato implementato numericamente su Simulink e sottoposto a simulazioni, in modo da stimarne le prestazioni, valutando se fossero o meno accettabili in termini di qualità di volo sull’intero inviluppo. Il sistema è stato poi simulato anche con l’introduzione di incertezze parametriche strutturate sulle derivate aerodinamiche, per verificarne la robustezza. L’analisi dei risultati ottenuti ha evidenziato come il sistema di controllo progettato abbia prestazioni soddisfacenti sull’intero inviluppo di volo e sia sufficientemente insensibile agli eventuali errori presenti nel modello

    On the integration of singularity-free representations of SO(3) for direct optimal control

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    In this paper we analyze the performance of different combinations of: (1) parameterization of the rotational degrees of freedom (DOF) of multibody systems, and (2) choice of the integration scheme, in the context of direct optimal control discretized according to the direct multiple-shooting method. The considered representations include quaternions and Direction Cosine Matrices, both having the peculiarity of being non-singular and requiring more than three parameters to describe an element of the Special Orthogonal group SO(3). These representations yield invariants in the dynamics of the system, i.e., algebraic conditions which have to be satisfied in order for the model to be representative of physical reality. The investigated integration schemes include the classical explicit Rungeâ\u80\u93Kutta method, its stabilized version based on Baumgarteâ\u80\u99s technique, which tends to reduce the drift from the underlying manifold, and a structure-preserving alternative, namely the Rungeâ\u80\u93Kutta Munthe-Kaas method, which preserves the invariants by construction. The performances of the combined choice of representation and integrator are assessed by solving thousands of planning tasks for a nonholonomic, underactuated cart-pendulum system, where the pendulum can experience arbitrarily large 3D rotations. The aspects analyzed include success rate, average number of iterations and CPU time to convergence, and quality of the solution. The results reveal how structure-preserving integrators are the only choice for lower accuracies, whereas higher-order, non-stabilized standard integrators seem to be the computationally most competitive solution when higher levels of accuracy are pursued. Overall, the quaternion-based representation is the most efficient in terms of both iterations and CPU time to convergence, albeit at the cost of lower success rates and increased probability of being trapped by higher local minima

    disrupting the pcsk9 ldlr protein protein interaction by an imidazole based minimalist peptidomimetic

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    We report on a tetraimidazole-based β-strand minimalist peptidomimetic as a novel inhibitor of LDLR–PCSK9 protein–protein interaction, a promising target for hypercholesterolemia

    CREB engages C/EBPδ to initiate leukemogenesis.

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    cAMP response element binding protein (CREB) is frequently overexpressed in acute myeloid leukemia (AML) and acts as a proto-oncogene; however, it is still debated whether such overactivation alone is able to induce leukemia as its pathogenetic downstream signaling is still unclear. We generated a zebrafish model overexpressing CREB in the myeloid lineage, which showed an aberrant regulation of primitive hematopoiesis, and in 79% of adult CREB-zebrafish a block of myeloid differentiation, triggering to a monocytic leukemia akin the human counterpart. Gene expression analysis of CREB-zebrafish revealed a signature of 20 differentially expressed human homologous CREB targets in common with pediatric AML. Among them, we demonstrated that CREB overexpression increased CCAAT-enhancer-binding protein-δ (C/EBPδ) levels to cause myeloid differentiation arrest, and the silencing of CREB-C/EBPδ axis restored myeloid terminal differentiation. Then, C/EBPδ overexpression was found to identify a subset of pediatric AML affected by a block of myeloid differentiation at monocytic stage who presented a significant higher relapse risk and the enrichment of aggressive signatures. Finally, this study unveils the aberrant activation of CREB-C/EBPδ axis concurring to AML onset by disrupting the myeloid cell differentiation process. We provide a novel in vivo model to perform high-throughput drug screening for AML cure improvement

    A utilização de um jogo sério em aulas introdutórias à educação financeira

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    Este artigo explora a utilização a utilização de Jogos Sérios como material de apoio pedagógico em aulas introdutórias à Educação Financeira, com o intuito de contribuir com a aprendizagem de conceitos introdutórios, voltada para estudantes adultos. Durante o desenvolvimento do jogo foram considerados estes conceitos relevantes, de forma a refleti-los no ambiente do jogo. O jogo foi aplicado em uma aula composta por três etapas: uma breve explanação teórica sobre Educação Financeira, uma explicação sobre o funcionamento e as regras do jogo, bem como o uso deste pelos estudantes, e a aplicação de um questionário para validar a contribuição do jogo como material pedagógico, incluindo aspectos técnicos relacionados a ele. Concluiu-se que o jogo cumpriu com sua meta de favorecer a aprendizagem dos conceitos propostos

    Efficient Walking Gait Generation via Principal Component Representation of Optimal Trajectories: Application to a Planar Biped Robot With Elastic Joints

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    Recently, the method of choice to exploit robot dynamics for efficient walking is numerical optimization (NO). The main drawback in NO is the computational complexity, which strongly affects the time demand of the solution. Several strategies can be used to make the optimization more treatable and to efficiently describe the solution set. In this letter, we present an algorithm to encode effective walking references, generated offline via numerical optimization, extracting a limited number of principal components and using them as a basis of optimal motions. By combining these components, a good approximation of the optimal gaits can be generated at run time. The advantages of the presented approach are discussed, and an extensive experimental validation is carried out on a planar legged robot with elastic joints. The biped thus controlled is able to start and stop walking on a treadmill, and to control its speed dynamically as the treadmill speed change

    Multicenter Evaluation of a 0-Hour/1-Hour Algorithm in the Diagnosis of Myocardial Infarction With High-Sensitivity Cardiac Troponin T

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    Study objectiveWe aim to prospectively validate the diagnostic accuracy of the recently developed 0-h/1-h algorithm, using high-sensitivity cardiac troponin T (hs-cTnT) for the early rule-out and rule-in of acute myocardial infarction.MethodsWe enrolled patients presenting with suspected acute myocardial infarction and recent (<6 hours) onset of symptoms to the emergency department in a global multicenter diagnostic study. Hs-cTnT (Roche Diagnostics) and sensitive cardiac troponin I (Siemens Healthcare) were measured at presentation and after 1 hour, 2 hours, and 4 to 14 hours in a central laboratory. Patient triage according to the predefined hs-cTnT 0-hour/1-hour algorithm (hs-cTnT below 12 ng/L and Δ1 hour below 3 ng/L to rule out; hs-cTnT at least 52 ng/L or Δ1 hour at least 5 ng/L to rule in; remaining patients to the “observational zone”) was compared against a centrally adjudicated final diagnosis by 2 independent cardiologists (reference standard). The final diagnosis was based on all available information, including coronary angiography and echocardiography results, follow-up data, and serial measurements of sensitive cardiac troponin I, whereas adjudicators remained blinded to hs-cTnT.ResultsAmong 1,282 patients enrolled, acute myocardial infarction was the final diagnosis for 213 (16.6%) patients. Applying the hs-cTnT 0-hour/1-hour algorithm, 813 (63.4%) patients were classified as rule out, 184 (14.4%) were classified as rule in, and 285 (22.2%) were triaged to the observational zone. This resulted in a negative predictive value and sensitivity for acute myocardial infarction of 99.1% (95% confidence interval [CI] 98.2% to 99.7%) and 96.7% (95% CI 93.4% to 98.7%) in the rule-out zone (7 patients with false-negative results), a positive predictive value and specificity for acute myocardial infarction of 77.2% (95% CI 70.4% to 83.0%) and 96.1% (95% CI 94.7% to 97.2%) in the rule-in zone, and a prevalence of acute myocardial infarction of 22.5% in the observational zone.ConclusionThe hs-cTnT 0-hour/1-hour algorithm performs well for early rule-out and rule-in of acute myocardial infarction

    The rapid spread of SARS-COV-2 Omicron variant in Italy reflected early through wastewater surveillance

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    The SARS-CoV-2 Omicron variant emerged in South Africa in November 2021, and has later been identified worldwide, raising serious concerns. A real-time RT-PCR assay was designed for the rapid screening of the Omicron variant, targeting characteristic mutations of the spike gene. The assay was used to test 737 sewage samples collected throughout Italy (19/21 Regions) between 11 November and 25 December 2021, with the aim of assessing the spread of the Omicron variant in the country. Positive samples were also tested with a real-time RT-PCR developed by the European Commission, Joint Research Centre (JRC), and through nested RT-PCR followed by Sanger sequencing. Overall, 115 samples tested positive for Omicron SARS-CoV-2 variant. The first occurrence was detected on 7 December, in Veneto, North Italy. Later on, the variant spread extremely fast in three weeks, with prevalence of positive wastewater samples rising from 1.0% (1/104 samples) in the week 5-11 December, to 17.5% (25/143 samples) in the week 12-18, to 65.9% (89/135 samples) in the week 19-25, in line with the increase in cases of infection with the Omicron variant observed during December in Italy. Similarly, the number of Regions/Autonomous Provinces in which the variant was detected increased from one in the first week, to 11 in the second, and to 17 in the last one. The presence of the Omicron variant was confirmed by the JRC real-time RT-PCR in 79.1% (91/115) of the positive samples, and by Sanger sequencing in 66% (64/97) of PCR amplicons. In conclusion, we designed an RT-qPCR assay capable to detect the Omicron variant, which can be successfully used for the purpose of wastewater-based epidemiology. We also described the history of the introduction and diffusion of the Omicron variant in the Italian population and territory, confirming the effectiveness of sewage monitoring as a powerful surveillance tool

    The rapid spread of SARS-COV-2 Omicron variant in Italy reflected early through wastewater surveillance

    Get PDF
    The SARS-CoV-2 Omicron variant emerged in South Africa in November 2021, and has later been identified worldwide, raising serious concerns. A real-time RT-PCR assay was designed for the rapid screening of the Omicron variant, targeting characteristic mutations of the spike gene. The assay was used to test 737 sewage samples collected throughout Italy (19/21 Regions) between 11 November and 25 December 2021, with the aim of assessing the spread of the Omicron variant in the country. Positive samples were also tested with a real-time RT-PCR developed by the European Commission, Joint Research Centre (JRC), and through nested RT-PCR followed by Sanger sequencing. Overall, 115 samples tested positive for Omicron SARS-CoV-2 variant. The first occurrence was detected on 7 December, in Veneto, North Italy. Later on, the variant spread extremely fast in three weeks, with prevalence of positive wastewater samples rising from 1.0% (1/104 samples) in the week 5–11 December, to 17.5% (25/143 samples) in the week 12–18, to 65.9% (89/135 samples) in the week 19–25, in line with the increase in cases of infection with the Omicron variant observed during December in Italy. Similarly, the number of Regions/Autonomous Provinces in which the variant was detected increased fromone in the first week, to 11 in the second, and to 17 in the last one. The presence of the Omicron variant was confirmed by the JRC real-time RT-PCR in 79.1% (91/115) of the positive samples, and by Sanger sequencing in 66% (64/97) of PCR amplicons
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